The present invention relates generally to exercise apparatus and, more particularly, to an isokinetic oscillating exercise apparatus which may be used to exercise different muscles by grasping by one hand or two hands centrally-located gripping portions attached to an elongated member and moving or shaking the member back and forth, causing the opposite ends of the member to oscillate.
Various exercise apparatus have been used in the past which a person may grasp by his or her hand and lift for the purpose of exercising particular arm muscles or other muscles of the body. For example, dumbbells are disclosed in U.S. Pat. Nos. 1,918,142, issued to Smith on Jul. 11, 1933; 1,013,782, issued to Koch on Jan. 2, 1912; and 460,270, issued to Somerby on Sep. 29, 1891. However, such dumbbells are used to exercise only isolated muscle groups, one group at a time, on only one side of a person's arm, depending on which direction the dumbbells are moved or lifted. As a result, muscle groups at opposite sides of a person's arm are not exercised simultaneously or at the same time by movement of the dumbbells.
An exercising device is described in U.S. Pat. No. 4,268,031, issued to Schomburg on May 19, 1981. The device has a hoop with a ball held at the center of the hoop by tensioned, radially-disposed elastic strings or lines. A user grasps the ball and moves it up and down, causing the hoop to oscillate up and down. However, the exercise benefits of this device are limited due to the flexibility of the elastic strings.
Another device providing minimal exercise benefits is shown in U.S. Pat. No. 3,545,121, issued to Micks on Dec. 8, 1970. This device has a sphere trapped between two springs on a shaft. A person is able to hold one end of the shaft and cause the sphere to slide up or down the shaft rebounding between the springs in response to hand and wrist movements. Still another device providing limited, if any, exercise benefits is disclosed in U.S. Pat. No. 4,305,582, issued to Barton on Dec. 15, 1981. This device is intended for use as an amusement device. Cylindrically-shaped sections held together by an elastic cord passing through longitudinal bores in the sections form a segmented elongated device. A user may shake, move or tip the device causing the sections to move relative to one another, and the ends of the device to oscillate. However, the sections of this device oscillate in a random unpredictable fashion making it difficult to use as an exercise device. Also, the elastic cord holding the sections together provides a weak design (may break), preventing steady and rapid oscillation of the sections.
U.S. Pat. No. 3,425,690, issued to Charbonnet on Feb. 4, 1969, describes a hoop held to a belt by elastic members such as ropes. The belt may be attached to the waist or head of a user, allowing the user to move the hoop vertically or cumferentially about the body due to corresponding movement of the user's body. This device cannot be used to simultaneously exercise muscles on both sides of a person's arm. Finally, an exercising device having a number of elongated rubber tubes passing through a rubber sleeve is disclosed in U.S. Pat. No. 1,254,974, issued to Briggs on Jan. 29, 1918. The sleeve functions like a handle and may be grasped and moved back and forth to cause the ends of the tubes to oscillate. Flexible elongated members such as rubber tubes are needed for the device because it is intended to be used to strike the arms, back, shoulders or other parts of a user, or to produce a massaging effect. However, the rubber tubes used for this device are so flexible that the exercise benefits of the device are significantly reduced.
Isokinetic exercise devices have been used in the past. Isokinetic exercise is an accommodating variable resistance in which the speed of motion of a limb to be exercised is set and the resistance accommodates to match the force applied. During this type of exercise, movement of the limb is performed at a constant angular velocity. Once a preset angular velocity is attained, resistance to movement is then determined by the effort of the person exercising. When isokinetic exercise is used, strength and power gains are excellent at faster speeds, and endurance is also developed at faster speeds. In addition, muscles on both sides of a limb are exercised during isokinetic exercise. However, past isokinetic exercise devices have been expensive to manufacture, usually requiring complicated and bulky equipment.